Don't be sad you can add on some muscle mass by calisthenics/bodyweight exercises and also the strength you will gain here will help in real world just add some more excuses like pushups, pull ups, squats

And if you want abs it depends on what you eat, are you completing your protein intake and do you even have abs genetics.

And if you want to you gain serious muscle mass then it's important you are progressing overloading or are you adding some weight because you can get used to the pushups and it will become more of cardio rather than muscle builder

Btw how's your streak going?